Scottish Beaver Trial publishes final report

The partner organisations behind the Scottish Beaver Trial, the first licensed release of a mammal species ever to take place in the UK, have published the Trial’s final report. The report details the entire process of the Scottish Beaver Trial, from capture of the Norwegian beavers, through their release and to the end of the monitoring period. This follows the publication last month of six independent scientific reports on the Trials and will help Scottish government ministers decide on the future of beavers in Scotland.

The Eurasian beaver (Castor fiber) is thought to have become extinct in England and Wales between the 12th and 13th centuries and in Scotland by the 16th century as a result of over-exploitation by humans. The beaver is widely considered to be a ‘keystone species’ in forest and riparian environments because, by modifying their habitats through their feeding, digging and damming behaviours, they have a significant and positive influence on ecosystem health and function.

The Scottish Beaver Trial – a partnership between the Scottish Wildlife Trust and the Royal Zoological Society of Scotland (RZSS) – received a licence from the Scottish government in May 2008 to undertake a five-year, scientifically monitored trial reintroduction of beavers to Knapdale Forest. Three families of beavers (totalling 11 animals) were subsequently released the following year within separate freshwater lochs.

Over the following five years, a detailed scientific monitoring programme collected data on the ecology of the released beavers and their impacts on the environmental features in and around the Trial area. Researchers also assessed the social and economic impacts of the Trials on nearby communities. The monitoring programme ceased in May 2014.

In line with their notoriety as ‘ecosystem engineers’, the beavers considerably changed the shape of woodland along loch shores. They also increased water levels in some of the lochs through dam building. The effects of beavers on trees led to a more open woodland canopy with a lower vertical density which, in turn, led to greater ground cover by grasses and woody debris and less leaf litter cover. The beavers also greatly altered aquatic plant communities through herbivory and water level rise, which had considerable impact on plant cover and, in places, led to increased species richness and heterogeneity. Moreover, newly inundated areas of the shoreline were rapidly colonised by aquatic plants which facilitated colonisation by a diversity of invertebrates.

Research on the socio-economic impact of the Trials concluded that there were “modest” benefits to local businesses, with slight increases observed in turnover. The authors of the report did, however, speculate that businesses might be able to boost earnings and job opportunities if the beavers were allowed to stay on a permanent basis. The Trials also generated high media interest, with the release day alone estimated to have reached over 10 million people via newspaper circulation. This contributed to 32,000 members of the general public, school and university students visiting Knapdale over the five years for guided walks and to attend talks.

The final results of the Trials will be collated and presented to the Scottish Government in May 2015, after which the Scottish Government will decide on the future of the Knapdale beavers and further beaver reintroductions. Supporters of further reintroductions will gain optimism from the findings of a YouGov poll which found that only 5% of the surveyed Scottish public opposed the reintroduction of beavers at a national scale, with 60% of survey respondents backing their reintroduction. Nevertheless, reservations have been expressed by some in the agricultural, forestry, fieldsports and fishing sectors in particular, who fear potential detrimental impacts that beavers may cause and have called for further trials to take place in more intensive farming and forestry areas before any decisions are made.

There are currently over 100 beavers living wild in the River Tay catchment and Scottish government ministers have previously shelved plans to trap the beavers due to concerns regarding the cost of such an exercise. Their future will also be reviewed next year.

European nations currently have a commitment to consider reintroductions of extinct native species under the EU’s Directive 92/43/EEC Conservation of Natural Habitats and Wild Flora and Fauna (the Habitats and Species Directive), Article 22. Beavers are often considered ‘flagship’ species and there is some evidence to suggest that their presence in the future might raise awareness about nature and conservation in the UK. With current biodiversity indicators painting a rather bleak picture for much of the UK’s existing native biodiversity, a decision to re-establish the beaver in parts of the UK would be a welcome break in an otherwise typical downward trend in the state of our wildlife.